Injection of a resin material from an injection device into a mold that has been clamped by a mold clamping device, to obtain a molded article, is commonly practiced. Resin pellets are typically employed as the resin material. The resin pellets are a granular solid so as to facilitate supply. The resin pellets are charged into a heating cylinder, where they undergo plasticization and kneading through heating and rotation of a screw, to obtain a fluidized material. This fluidized material is injected into a mold, and solidified to a molded article.
When the resin material is silicone rubber, the resin material takes the form of a liquid material prior to supply to the injection device. Such materials of liquid form prior to supply to the injection device are termed “liquid resin materials.”
A two-pack liquid resin material is one example of such a liquid resin material. In a two-pack liquid resin material, one liquid is the main component, and the other liquid is an additive, typically a hardener. When the hardener is combined with the main component, the action of the hardener brings about hardening to a predetermined level of hardness, within several hours to several tens of hours at normal temperature, or several tens of seconds to several tens of minutes at molding temperature.
When a hardener is used, it is recommended to add the hardener as late as possible, in order to avoid clogging of the flow channel. Such a liquid resin material supply device is disclosed in, for example, Japanese Patent No. 4373932. The configuration of the liquid resin material supply device will be described with reference to FIG. 11.
FIG. 11 is a principle diagram of a prior art liquid resin material supply device. A main component 201 is fed to a metering cylinder 203 by a pump 202. After being metered by the metering cylinder 203, the main component 201 is supplied to a heating cylinder 205 of an injection device 204. Additionally, a hardener 206 is fed to a metering cylinder 208 by a pump 207. After being metered by the metering cylinder 208, the hardener 206 is supplied to the heating cylinder 205 of the injection device 204. The main component 201 and the hardener 206 are kneaded by a screw 209 in the heating cylinder 205, and thereafter injected as shown by an arrow 211.
However, the liquid resin material supply device disclosed in Japanese Patent No. 4373932 necessitates the injection device 204. Because the injection device 204 is expensive, the device cost of the liquid resin material supply device is greater. Also, in the injection device 204, mixing is accomplished by a screw 209, and there is a risk that the screw 209 will fail to mix the material thoroughly. Further, during mixing by the screw 209, outside air may get sucked into the heating cylinder 205, posing a concern that air bubbles will remain in the molded article. Thus, the fact that the injection device 204 is necessary gives rise to a number of problems.
Accordingly, there exists a need for a liquid resin material molding system that does not require an injection device, and that affords thorough mixing of material without air bubbles getting entrained therein.